Evidencias petrográficas de interacción entre un magma félsico y un nivel sedimentario rico en radiolarios en la Faja Pirítica Ibérica

Abstract

In the South Portuguese Zone (Hercynian Iberian Massif), carboniferous volcaniclastic and sedimentary sequences accumulated in a submarine environment were penetrated by subvolcanic intrusions during or shortly after deposition. To the west of El Villar (Huelva), dispersed peperites were produced when a felsic sill underwent quenching, disruption and mingling with wet, unconsolidated sediments. Likely, these phenomena took place during the first stages of the sill emplacement. Subsequently, isolated clasts experienced cooling-contraction fragmentation, releasing shards of quenched rhyolite into the adjacent sediment. Interaction between magma and wet sediment was non-explosive and involved fluidization of the host sediments, creating space for the intruding magma and causing pervasive injection of highly mobile sediment a long thermal contraction and perlitic cracks, both in the felsic sill and clasts